Cotter pins are used frequently to secure the position or location of a movable body relative to another body when strength is not of primary importance. A well-known form of a cotter pin includes an elongated body folded back on itself to provide a loop or head with tines extending therefrom parallel to one another. Frequently, one of the tines is longer than the other. When new, the tines of a cotter pin lie closely adjacent each other. In cross-section, the tines are solid semi-cylinders and the appearance in end view of the tines overlying each other is that of a split cylinder.
In a known application for a cotter pin, the pin is inserted through a hole in a shaft or other body, with the looped head of the cotter pin disposed against the body at the entrance to the hole. At the opposite side of the body, the tines projecting through the hole are bent in opposite directions to prevent the cotter pin from being extracted from the hole unless the tines are straightened. The bends in the tines are formed closely adjacent the body so that the cotter pin has limited axial movement, being restrained by the head against one side of the body and by the bends of the tines on the opposite side of the body.
Cotter pins have been used to retain sleeves, washers and other bodies on shafts and have been used as locking keys to further secure the location of a nut on a threaded shaft or bolt against unintended movement or “walking” along the threads. Other examples of the use of cotter pins include use to restrain clevis pins, hitch pins and the like from unintended extraction, and securing loosely fitting control arms on shafts and bodies of various types. Accordingly, cotter pins are provided in many different sizes, both in overall length and in the diameter of the overlying tines, from very short and thin to relatively long and thick.
Known cotter pins are simple devices that are manufactured quite easily. Accordingly, a significant portion of the manufacturing cost involved in providing cotter pins is in the cost of the material from which the cotter pin is made. Cotter pins are often made of steel and other expensive metals. It is desirable to reduce the cost of cotter pins, which often are used only one time and discarded if removed, being replaced by a new cotter in the reassembled device.
Even as simple as cotter pins are, difficulties can be encountered in the installation of known cotter pins, particularly with larger cotter pins. As described previously, a cotter pin is inserted through a hole. In a preferred arrangement, the hole is only minimally wider than the tines of the cotter pin. If the shaft or other body on which the cotter pin is used is of relatively large diameter, the hole therethrough is quite long. It is desirable that the cotter pin fit relatively snuggly within the hole so that it does not move and wear unnecessarily during use. According, a substantial portion of the surface area of the tines in the hole frictionally engages the surface of the hole as the cotter pin is inserted. Since known cotter pins have been in the configuration of split cylinders, sliding a large cotter pin through a long receiving hole can require significant force, especially if the opposed tines are separated slightly providing outward force against the inner surface of the hole. Further, the tines of large cotter pins are relatively thick and can be difficult to bend, particularly if the cotter pin is in an area of limited accessibility.
What is needed is a cotter pin design that can be used for cotter pins of various sizes to manufacture cotter pins less expensively than known designs and to facilitate the use of cotter pins.